The methods of connecting a Micro Electro-Mechanical system (MEMS) device to an electronic device for driving the MEMS device (a driving circuit device), e.g., an application specific integrated circuit (ASIC) chip, can be classified into three types.
In a first method, an upper, lower, or side portion of a packaged MEMS device is connected to an MEMS driving electronic device using Au wire bonding. In a second method, the packaged MEMS device is bonded to the MEMS driving electronic device using flip-chip bonding. In a third method, the MEMS device and the MEMS driving electronic device are manufactured on a wafer and then connected to each other using electrodes.
However, in the first method, a difference in electrical characteristics occurs between a designed MEMS device and a manufactured MEMS device due to a parasitic resistance, a parasitic capacitance, etc. caused by the wire bonding. In particular, if the MEMS device is a circuit detecting a capacitance to be driven, a signal-to-noise ratio (SNR) is reduced due to the wire bonding which reduces the entire electrical characteristics of the MEMS device. In the second method, the parasitic capacitance and resistance, etc. may be reduced. However, the MEMS device is packaged and then bonded to the MEMS driving electronic device. Thus, a chip level package may be manufactured, but a wafer level package may not be manufactured. In the third method, if the MEMS device and the MEMS driving electronic device are manufactured on a wafer using the same method, losses caused by a package may be reduced.
However, in the third method, yield may be more reduced than when the MEMS device and the MEMS driving electronic device are manufactured on different wafers, due to yield variables of the MEMS device and the MEMS driving electronic device. In other words, the third method requires large amounts of cost and time to mass-produce MEMS chips and MEMS driving electronic devices.